1. Field of the Invention
The present invention is related to the field of hollow fiber membranes and hollow fiber filtration modules.
2. Description of Related Art
Hollow fiber filtration modules are useful in a variety of filtration processes and generally suitable for immersion in the fluid to be filtered. Standard hollow fiber filtration modules contain bundles of hollow fiber membranes that are secured at each end by a header piece. The hollow fiber membranes generally are secured in place within the header by a potting compound that surrounds the fibers near each end, secures them in place with respect to the other hollow fiber membranes and the header and forms a seal around the membranes. However, both ends of the individual hollow fiber membranes remain open to allow fluid to flow into and/or out of the ends of the membrane through the potting compound.
In another type of hollow fiber filtration module, a single-header filtration module, the hollow fiber membranes are secured by a header at only one end. The other end of the bundle is not secured with a header, and the unsecured ends of the hollow fiber membranes can move freely with respect to each other. In some module designs, movement of the free ends is restricted by a housing, or the unsecured ends are supported by a frame. In other designs the entire fiber bundle may be encased in a housing. In yet other designs the free ends of the membranes are supported only by the fluid in which the filtration module is immersed. In most designs, the free ends of the hollow fiber membranes are sealed to prevent fluid flow into or out of the free ends of the membranes.